Movement No. 142 demonstrates a sophisticated mechanism used in silk machinery to automatically vary the stroke length of a traversing guide-bar that winds silk onto spools or bobbins. A large circular disk rotates on a fixed central stud, which has a pinion fixed to its end. A spur-gear is carried on the disk and meshes with the fixed central pinion — so as the disk rotates, the spur-gear is forced to rotate partially on its own center due to the fixed pinion. A small crank is bolted to the spur-gear, connected via a connecting-rod to the traversing guide-bar. As the disk revolves, the partial rotation of the spur-gear gradually moves the crank closer to or farther from the center of the disk — thereby shortening or lengthening the effective crank radius and thus the stroke of the guide-bar. Over one full revolution of the spur-gear, the traverse length first decreases then increases by equal amounts, creating a rhythmically varying stroke that builds up silk layers of varying widths on the bobbin.
142. Movement used for varying the length of the traversing guide-bar which, in silk machinery, guides the silk on to spools or bobbins. The spur-gear, turning freely on its center, is carried round by the larger circular disk, which turns on a fixed central stud, which has a pinion fast on its end. Upon the spur-gear is bolted a small crank, to which is jointed a connecting-rod attached to traversing guide-bar. On turning the disk, the spur-gear is made to rotate partly upon its center by means of the fixed pinion, and consequently brings crank nearer to center of disk. If the rotation of disk was continued, the spur-gear would make an entire revolution. During half a revolution the traverse would have been shortened a certain amount at every revolution of disk, according to the size of spur-gear; and during the other half it would have gradually lengthened in the same ratio.